Developing device including toner hopper and toner cartridge stirring portions

Abstract

A developing device suitable for use in an electrophotographic recording apparatus includes either a toner stirring portion arranged in a toner hopper portion, the toner stirring portion being provided with a portion for varying toner conveying speed, or in the toner a toner stirring and moving means provided in a toner cartridge. A printing irregularity does not occur on a printing paper even if the printing is performed at the state where the amount of toner, which is collected in the toner hopper portion, is too reduced to sufficiently cover the toner hopper stirring portion.

What is claimed is: 
     
       1. A developing device comprising a developing portion for supplying toner to an electrostatic latent image on a photoconductor drum and developing said latent image, a toner hopper portion for collecting toner therein and supplying the toner to the developing portion, a stirring portion disposed in the toner hopper portion and composed of a shaft; and first and second helical members which are wound around the shaft in the directions opposite to each other wherein the first and second helical members are turned to thereby stir a part of the toner and convey the same toward the central portion of the toner hopper portion; the first and second helical members being formed of coil shaped members, respectively; and the first and second helical members being provided with first and second toner conveying speed varying portions for changing the conveying speed of toner, respectively. 
     
     
       2. A developing device according to claim 1, wherein the first and second toner conveying speed varying portions are formed by reducing winding diameters at given positions of the first and second helical members, respectively. 
     
     
       3. A developing device according to claim 1, wherein the first and second toner conveying speed varying portions comprise first toner conveying speed varying portions formed by reducing the winding diameters at given portions of the first and second helical members and second toner conveying speed varying portions formed by reducing winding pitches at given portions of the first and second helical members; the first toner conveying speed varying portions being provided at given portions on the first and second helical portions at the given positions and given intervals; the second toner conveying speed varying portions being provided between the given positions of the first and second helical portions and the ends of the toner conveying direction sides. 
     
     
       4. A developing device according to claim 1, wherein the toner conveying speed varying portions are formed by reducing winding pitches of the first and second helical members and wherein the toner conveying speed varying portions are provided on the first and second helical portions between given positions of the first and second helical portions and the ends of the toner conveying direction sides. 
     
     
       5. A developing device according to claim 1, wherein the toner conveying speed varying portions are formed by gradually reducing winding diameters of the first and second helical members in the toner conveying directions and wherein the toner conveying speed varying portions are provided on the first and second helical portions between given positions of the first and second helical portions and the ends of the toner conveying direction sides. 
     
     
       6. A developing device comprising a developing portion for supplying toner to an electrostatic latent image on a photoconductor drum and developing said latent image, said developing portion including a developing roller having an axis extending in a direction parallel to an axis of said photoconductor drum;   a toner cartridge, said toner cartridge including a toner cartridge stirring portion comprising third and fourth helical members wound in opposite directions;   a toner cartridge mounting portion for mounting said toner cartridge;   a toner hopper portion for collecting toner supplied from said toner cartridge and supplying the toner to said developing portion, said toner hopper portion including a toner hopper stirring portion comprising first and second helical members wound in opposite directions; and   a driving means for stirring and conveying toner in a direction parallel to the axis of said developing roller toward a central portion or toward end side portions of the toner hopper portion by turning the first and second helical members of the toner hopper stirring portion, and for stirring and conveying toner in the toner cartridge in a direction parallel to the axis of said developing roller and opposite to the conveying direction of the toner in the toner hopper stirring portion by turning the third and fourth helical members of the toner cartridge stirring portion.   
     
     
       7. A developing device comprising a photoconductor drum for forming an electrostatic latent image on the peripheral surface thereof by charging with electricity by a charging means and by exposing the same by a light emitting means; a developing portion for supplying toner to the latent image on the outer periphery of the photoconductor drum and developing the latent image; a toner hopper portion for collecting toner therein and for supplying the toner to the developing portion; a toner stirring means composed of a shaft and first and second helical members which are wound around the shaft in the directions opposite to each other; a cleaning means for removing the toner which has not been transferred in a transfer process but remains on the outer periphery of the photoconductor drum; a toner conveying means for conveying the removed toner to the portion close to the end portion of the toner stirring portion wherein the first and second helical members are turned to thereby stir the toner and convey the toner toward the central portion of the toner hopper portion; the first and second helical members being formed of coiled members, said coiled members having the same outer diameters and winding pitches; the first and second helical members being respectively provided with toner conveying speed varying portions for changing the conveying speed of the toner. 
     
     
       8. A developing device according to claim 7, wherein the toner conveying speed varying portions are formed by reducing winding diameters of the first and second helical members and wherein the toner conveying speed varying portions are provided at given positions of the first and second helical portions. 
     
     
       9. A developing device according to claim 8, wherein the toner conveying speed varying portions are formed so as to contact the coils to the shaft and wherein the given positions of the coils on the first and second helical members are adjacent to the middle portions of the first and second helical members. 
     
     
       10. A developing device according to claim 7, wherein the toner conveying speed varying portions comprise first toner conveying speed varying portions formed by reducing the winding diameters of given portions of the first and second helical members and second toner conveying speed varying portions formed by reducing winding pitches of the first and second helical members; the first toner conveying speed varying portions being provided on the first and second helical portions at the given positions and given intervals; and wherein the second toner conveying speed varying portions are provided on the first and second helical portions between the given positions of the first and second helical portions and the ends of the toner conveying direction sides. 
     
     
       11. A developing device according to claim 10, wherein the toner conveying speed varying portions are formed so as to contact the coils to the shaft, the first toner conveying speed varying portions being provided at positions adjacent to the middle portions of the first and second helical members; and wherein the second toner conveying speed varying portions are provided between the ends of the toner conveying direction sides of the first and second helical members and the first toner conveying speed varying portions. 
     
     
       12. A developing device according to claim 7, wherein the toner conveying speed varying portions are formed by reducing winding diameters of the first and second helical members, and wherein the toner conveying speed varying portions are provided on the first and second helical portions between given positions of the first and second helical portions and the ends of the toner conveying direction sides. 
     
     
       13. A developing device according to claim 12, wherein the given positions on the first and second helical members are adjacent to the middle portions of the first and second helical members. 
     
     
       14. A developing device according to claim 7, wherein the toner conveying speed varying portions are formed by gradually reducing winding diameters of the first and second helical members toward the toner conveying directions, and wherein the toner conveying speed varying portions are provided on the first and second helical portions between given positions of the first and second helical portions and the ends of the toner conveying direction sides. 
     
     
       15. A developing device according to claim 14, wherein the given positions on the first and second helical members are adjacent to end portions of the first and second helical members. 
     
     
       16. A developing device according to claim 7, wherein the toner conveying speed varying portions are formed by gradually reducing winding pitches of the first and second helical members toward the toner conveying directions, and wherein the toner conveying speed varying portions are provided on the first and second helical portions between given positions of the first and second helical portions and the ends of the toner conveying direction sides. 
     
     
       17. A developing device according to claim 16, wherein the given positions on the first and second helical members are adjacent to the end portions of the first and second helical members. 
     
     
       18. A developing device comprising a photoconductor drum for forming an electrostatic latent image on the peripheral surface thereof by charging said drum with electricity by a charging means and by exposing said drum to a light emitting means;   a developing portion for supplying toner to the latent image on the outer periphery of the photoconductor drum and developing the latent image, said developing portion including a developing roller having an axis extending in a direction parallel to an axis of said photoconductor drum;   a toner hopper portion for collecting the toner therein and for supplying the toner to the developing portion;   a toner stirring means composed of a shaft; and   first and second helical members wound around the shaft in opposite directions, the first and second helical members being formed of coiled members having the same outer diameters and winding pitches;     a toner cartridge portion, having opposite ends, for storing the toner therein and for supplying the toner to the toner hopper portion, said toner cartridge including a toner cartridge stirring portion comprising third and fourth helical portions wound in opposite directions, the third and fourth helical members having the same diameters and winding pitches;   a toner cartridge mounting portion for mounting the toner cartridge;   a cleaning means for removing toner which remains on the outer periphery of the photoconductor drum;   a toner conveying means for conveying the removed toner to a portion close to an end portion of the toner stirring portion wherein the first and second helical members are turned to thereby stir the toner and convey the toner in a direction parallel to the axis of said developing roller and toward a central portion of the toner hopper portion; and   a driving means for turning the third and fourth helical members of the toner cartridge stirring means to thereby stir the toner in the toner cartridge and convey the toner in a direction parallel to the axis of said developing roller and toward the opposite ends of the toner cartridge.   
     
     
       19. A developing device which includes a developing member for supplying toner to an electrostatic latent image on a photoconductor drum and developing said latent image, said developing member including a developing roller having an axis extending in a direction parallel to an axis of said photoconductor drum, comprising: a toner hopper for collecting toner therein and supplying said toner to the developing member, said toner hopper having a central portion; and   a stirring member disposed in the toner hopper, said stirring member including a shaft having first and second opposite ends and a central portion therebetween; and   first and second helical members wound around said shaft in opposite directions, said first helical member being positioned between the first end and the central portion of said shaft, and said second helical member being positioned between the second end and the central portion of said shaft, each of said helical members having a first coil-shaped portion of predetermined diameter and pitch positioned at an end side portion adjacent the first end of said shaft and a second coil-shaped portion of predetermined diameter and pitch positioned at a central side portion adjacent the central portion of said shaft, said first and second helical members being rotated by said shaft to stir a part of the toner and convey said part of the toner in a direction parallel to the axis of said developing roller and toward the central portion of said hopper, the diameter and pitch of said helical coils determining the speed with which said toner is conveyed to the central portion of said toner hopper portion.     
     
     
       20. A developing device which includes a developing member for supplying toner to an electrostatic latent image on a photoconductor drum and developing said latent image, said developing device comprising: a toner hopper for collecting toner therein and supplying said toner to the developing member, said toner hopper having a central portion; and   a stirring member disposed in the toner hopper, said stirring member including a shaft having first and second opposite ends and a central portion therebetween; and   first and second helical members wound around said shaft in opposite directions, said first helical member being positioned between the first end and the central portion of said shaft, and said second helical member being positioned between the second end and the central portion of said shaft, each of said helical members having a first coil-shaped portion of predetermined diameter and pitch positioned at an end side portion adjacent the first end of said shaft and a second coil-shaped portion of predetermined diameter and pitch positioned at a central side portion adjacent the central portion of said shaft, said first and second helical members being rotated by said shaft to stir a part of the toner and convey said part of the toner toward the central portion of said hopper, the diameter and pitch of said helical coils determining the speed with which said toner is conveyed to the central portion of said toner hopper portion, each of said first and second helical members further comprising a toner conveying speed portion located between said first and second coil-shaped portions, said toner conveying speed varying portion being closely wound around said shaft and having a diameter which is less than that of said first and second helical coils.     
     
     
       21. A developing device according to claim 20 wherein the pitch of the second coil-shaped portion of each of said first and second helical members is less than that of said first coil-shaped portion. 
     
     
       22. A developing device which includes a developing member for supplying toner to an electrostatic latent image on a photoconductor drum and developing said latent image, said developing device comprising: a toner hopper for collecting toner therein and supplying said toner to the developing member, said toner hopper having a central portion; and   a stirring member disposed in the toner hopper, said stirring member including a shaft having first and second opposite ends and a central portion therebetween; and   first and second helical members wound around said shaft in opposite directions, said first helical member being positioned between the first end and the central portion of said shaft, and said second helical member being positioned between the second end and the central portion of said shaft, each of said helical members having a first coil-shaped portion of predetermined diameter and pitch positioned at an end side portion adjacent the first end of said shaft and a second coil-shaped portion of predetermined diameter and pitch positioned at a central side portion adjacent the central portion of said shaft, said first and second helical members being rotated by said shaft to stir a part of the toner and convey said part of the toner toward the central portion of said hopper, the diameter and pitch of said helical coils determining the speed with which said toner is conveyed to the central portion of said toner hopper portion, the pitch of the second coil-shaped portion of each of said first and second helical members being less than that of said first coil-shaped portion.     
     
     
       23. A developing device which includes a developing member for supplying toner to an electrostatic latent image on a photoconductor drum and developing said latent image, said developing device comprising: a toner hopper for collecting toner therein and supplying said toner to the developing member, said toner hopper having a central portion; and   a stirring member disposed in the toner hopper, said stirring member including a shaft having first and second opposite ends and a central portion therebetween; and   first and second helical members wound around said shaft in opposite directions, said first helical member being positioned between the first end and the central portion of said shaft, and said second helical member being positioned between the second end and the central portion of said shaft, each of said helical members having a first coil-shaped portion of predetermined diameter and pitch positioned at an end side portion adjacent the first end of said shaft and a second coil-shaped portion of predetermined diameter and pitch positioned at a central side portion adjacent the central portion of said shaft, said first and second helical members being rotated by said shaft to stir a part of the toner and convey said part of the toner toward the central portion of said hopper, the diameter and pitch of said helical coils determining the speed with which said toner is conveyed to the central portion of said toner hopper portion, the diameter of said first helical member gradually decreasing from the portion thereof adjacent the first end of said shaft to the portion thereof adjacent the central portion of said shaft, and the diameter of said second helical member gradually decreasing from the portion thereof adjacent the second end of said shaft to the portion thereof adjacent the central portion of said shaft.     
     
     
       24. A developing device according to claim 23 wherein the pitch of each of said first and second helical member is constant. 
     
     
       25. A developing device which includes a developing member for supplying toner to an electrostatic latent image on a photoconductor drum and developing said latent image, said developing device comprising: a toner hopper for collecting toner therein and supplying said toner to the developing member, said toner hopper having a central portion; and   a stirring member disposed in the toner hopper, said stirring member including a shaft having first and second opposite ends and a central portion therebetween; and   first and second helical members wound around said shaft in opposite directions, said first helical member being positioned between the first end and the central portion of said shaft, and said second helical member being positioned between the second end and the central portion of said shaft, each of said helical members having a first coil-shaped portion of predetermined diameter and pitch positioned at an end side portion adjacent the first end of said shaft and a second coil-shaped portion of predetermined diameter and pitch positioned at a central side portion adjacent the central portion of said shaft, said first and second helical members being rotated by said shaft to stir a part of the toner and convey said part of the toner toward the central portion of said hopper, the diameter and pitch of said helical coils determining the speed with which said toner is conveyed to the central portion of said toner hopper portion, the pitch of said first helical member gradually decreasing from the portion thereof adjacent the first end of said shaft to the portion thereof adjacent the central portion of said shaft, and the pitch of said second helical member gradually decreasing from the portion thereof adjacent the second end of said shaft to the portion thereof adjacent the central portion of said shaft.     
     
     
       26. A developing device according to claim 25 wherein the diameter of each of said first and second helical member is constant.